Cross-axis control for three or four roll calenders

ABSTRACT

Control system for profile adjustment of a property on an elongated sheet material, such as a rubber, during the manufacturing thereof. The system can include two gauges disposed on the output side of the manufacturing apparatus, one gauge being movable between an edge and the center portion of the sheet and the other gauge being at the other sheet edge. The manufacturing apparatus has a first actuator for adjusting the property at one sheet end portion and a second actuator for adjusting the property at the other end portion. The first and second actuators together act to adjust the property across the entire width of the material including a central portion intermediate to the end portions. A third actuator adjusts the central portion property in relation to the end portions. The gauges are coupled to a controller that periodically activates the first and second actuators together with the gauges at the end portions and the third actuator separately with the one gauge at the center portion. The first and second actuators are energized, upon actuation, to restore the end portions to their respective target values. The third actuator is energized, upon actuation, by the controller means only when the difference between the central portion property and the property of one of the end portions deviates from a predetermined amount. When there is such a deviation the third actuator initiates an adjustment that returns the central portion to match the edge value.

United States Patent Hays et al.

[ 51 Sept. 19, 1972 154] CROSS-AXIS CONTROL FOR THREE OR FOUR ROLL CALENDERS [72] Inventors: Willard C. Hays, Columbus; James D. Smith, Cleveland, both of Ohio [73] Assignee: Industrial Nucleonics Corporation [22] Filed: June 29, 1971 21 Appl.No.: 158,098

Related 1.1.8. Application Data 63] Continuation of Ser. No. 751,013, May 15, 1968, abandoned, which is a continuation of Ser. No. 362,448, April 24, 1964, abandoned.

52 vs. Cl. ..100/41,72/16, 100/47, 100/168, 250/833 [51] Int. Cl. ..B30b 11/22 [58] Field of Search ..72/10, l1, 12, 16; 100/35, 100/41, 47, 168; 162/259; 250/52, 83.3

[56] References Cited UNITED STATES PATENTS 2,792,730 5/1957 Cozzo ..l00/47 UX 3,000,438 9/1961 Alexander 162/259 3,006,225 10/1961 Mamas ..100/47 UX 2,355,391 8/1944 Nelson et al ..34/4' 3,179,800 4/1965 McNamara ..250/52 3,212,127 10/1965 Flock et al. 100/47 UX Primary Examiner-Billy J. Wilhite Attorney-William T. Fryer, 111, C. Henry Peterson, James J. OReilly and Cushman, Darby & Cushman [57] ABSTRACT Control system for profile adjustment of a property on an elongated sheet material, such asa rubber, during the manufacturing thereof. The system can include two gauges disposed on the output side of the manufacturing apparatus, one gauge being movable between an edge and the center portion of the sheet and the other gauge being at the other sheet edge. The manufacturing apparatus has a first actuator for adjusting the property at one sheet end portion and a second actuator for adjusting the property at the other end portion. The first and second actuators together act to adjust the property across the entire width of the material including a central portion intermediate to the end portions. A third actuator adjusts the central portion property in relation to the end portions. The gauges are coupled to a controller that periodically activates the first and second actuators together with the gauges at the end portions and the third actuator separately with the one gauge at the center portion. The first and second actuators areenergized, upon actuation, to restore the end portions to their respective target values. The third actuator is energized, upon actuation, by the controller means only when the difference between the central portion property and the property of one of the end portions deviates from a predetermined amount. When there is such a deviation the third actuator initiates an adjustment that returns the central portion to match the edge value.

44 Claims, 10 Drawing Figures PATENTEnsEm I972 3.691.940 sum 1 or 6 if E? T g2 F A fi J L Fk\\\\\\\\\\\\\\\\\\\ X k\\ 1 X (a) (a) AX \&\\\\ l x (A) (b) X+AX (c) (c) z I/II CONTROLLER MEANS GAUGE T I flag GAUGE 1%? JAcTu- GAUGE ATOR INVENTORS WILLARD C. HAYS JAMES D. SMITH BY 7W1:

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I NVEN'I'ORS WILLARD C. HAYS JAMES D. SMITH BY 7W1 PATENTED SEP 1 9 I972 .3 6 91, 94 O SHEET 3 0F 6 3 AXIS OFROLL 25 4o 44 24 B L c AXIS FROLL26 4o 44 24 43 1\ .-A L c 5 R A%/') B (c) 40 44 g4 43 A 4 l /L 9 X+AX '"X+A k (e) \B t T I GAUGE CONTROLLER MEANS I07 I25 I 4 L --w 1 Q INVENTORS WILLARD C. HAYS "4 JAMES D. SMITH BY GMT 7%:1:

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' saw u or 6 D SERVO J52 I I I I I I I I I I I I l I I I MIIWF g 3 '67 l l7O o CROSS AXIS ACTUATOR TARGET KNOB/ I +IIMIII- 5 I I I I |3Q 1 I43 I SIDE I I ACTUATOR L] l i I l g I TO I POSITIONER I I SWITCH 49 i 1 TIMER i I 23 I lllllll INVENIORS I I31 I WILLARD c. HAYS o f 24 g JAMES 0. SMITH w E g [I32 I BY wuw T 7 IL 8 MEASURING 7" SERVO ATTORNEY PATENTEDSEP l 9 m2 SHEET 5 0F 6 ASURING SERVO LEFT sum-z TO ACTUATOR LEFT END PORTION WILLARD C- HAYS 9 m a m Mfifl m MM 5 CXU UTT I (I: m AT THR TH R oc\ m m c M TA P WM W T 0 T u T, 2 m z u IIIVII. I

u I. G N o V UR 5E I S E 5 M o 2 m m l 4 4 I I l I I l l I ll D W5 T aw m n M RN 2 4 ,2 AK 0 3 4 T R 2 2 RIGHT SIDE JAMES 0. SMITH BY mum T QM ATTORNEY PATENTEDSEP I 9 I972 SHEET 6 OF 6 MEASURING SERVO MEASURING SERVO SCANNING CONTROL I I I-29I MENTOR-S WILLARD C. HAYS m T NR A N I m :mw E TA Ru T no... N P: I m A I 5 h. I 6 3 I P 2 O I 1 0M 3 mm 1 4 y n 8 R 0* A 5 6 aLuvnp w wm 6 7 MW 1 RA 8 /nc c 2 in 3 X I u o a 2 e N 2 R T \b TA M TRU G I I I I 1 III FOT E E P C T L A m 6 l I I I I I I I I I I I I I CONTROL UNIT JAMES D. SM TH ATTORNEY CROSS-AXIS CONTROL FOR THREE OR- FOUR I ROLL CALENDERS This application is a continuation of Ser. No. 751,013, filed May 15, 1968, and now abandoned, the latter case being a continuation of Ser. No. 362,448, filed Apr. 24, 1964, and now abandoned.

The present invention is related to the art of measurement and control of a material property. More particular, the present invention is concerned with the adjustment of'the property profile (along'a dimension transverse to'the elongation of the material) to achieve a desired specification.

The preferred embodiments of apparatus and method described herein are for adjusting the thickness or weight per unit area of an elongated material. However, other properties, such as moisture, hardness, and the like, can be controlled in accordance with 'the present invention.

Many industries produce materials that are formed, at least in one phase, as an elongated strip or sheet. The material is shaped to the configuration that meets desired specificationsQDeviations from these specifications may seriously affect the quality of the product and/or significantly increase the cost. For these reasons, it is imperative that the material be maintained continuously at the desired specifications and that any deviations be corrected as rapidly as possible.

The material configuration usually is dependent on several variables controlled by one or more adjustments in an apparatus. For example, U.S. Pat. No. 2,792,730, to G. Cozzo, issued May 21, 1957, described an apparatus for forming metal that has three separate adjustments, including roll bending, to control the profile. As another example, U.S. Pat. No. 3,006,225 to L. G. Mamas, issued Oct. 31, 1961, described a mill that shaped a sheet material using cross-axis as well as two other adjustments.

The prior art practice was to control these adjustments separately in response to individual, set targets. A .gauge would measure a linear dimension (thickness) or weight per unit area and a controller would compare the measurement with a target value and affect a control action to restore the material to the target value. However, it was found that in many apparatuses one or more adjustments would cause a change in a portion of the material controlled by another adjustment. The interrelation or interaction between the adjustments is an important factor in the design of a control system for such apparatus. In the following description, the term linear dimension means the same as thickness and is equivalent to weight per unit area with a substantially constant density material.

Another factor was the type of material variation. In other words, the profile linear dimension change measured in a material portion could be due to a machine direction variation (a non-uniform thickness in the direction of the material movement) or a linear dimension variation only in a direction transverse to the direction of material movement. The proper adjustment(s) that correct for profile variations depend on where the variations are located on the material and the cause of the variation.

A particularly difficult problem is encountered in the control of apparatus having first and second control means that adjust the linear dimension of the material end portions and a third control means that adjusts the relation between the 'end portions linear dimensions and a center portionlinear dimension. The first and second control means together change the linear dimension across the entire width of the material including the center portion. According to the prior art practice for adjusting this-type'of apparatus with two gauges, for example, the first and second control means, controlling the end portions, were activatedand one or both of them were energized to bring the respective end portion linear dimensions to target value(s). One gauge was'programed to the'center portion and the first and second control means were deactivated. The third control means was activated and energized to bring the center portion linear dimension to a target value. This activation cycle was repeated until the sheet was at desired target value(s). Using the aforementioned practice, several control actions could occur before reaching 'thedesir'ed specification, especially during activation of the third control means, when the profile change was due to a machine direction variation.

It is'an'object of the'present invention to provide an improved method and systems for controlling a property profile of an elongated material to a desired specification.

It is a further object of the present invention to provide a method and systems for controlling the formation of an elongated material with an apparatus having several interrelated adjustments for altering the material profile.

Another object of the present invention is to provide a method that corrects for variations in material profile in a minimum time when there is (l) a machine direction variation over or (2) a variation only across the width of the material.

These and other objects of the present invention are achieved by a method which can be practiced on an apparatus that has a first and second control means for separately adjusting the material property at the opposite end portions respectively and for together adjusting the material property at the end portions and in the sheet central portion intermediate the ends, and a third control means for adjusting the property of the central portion in relation to the material property at the end portions. The first and second control means and third control means are adjusted to maintain the material ends at target value(s). The third control means is energized only when the difference between the central portion property and the property at one of the material end portions deviates from a predetermined amount to reduce the difference to the predetermined amount. With this method the central portion is not changed if the apparent profile variation is due to a subsequent machine direction variation. The profile is corrected by adjustment of the control means at the opposite ends that uniformly restore the profile to the desired specification.

One control system of the present invention, for example, includes two gauges disposed on the output side of an apparatus, one gauge being movable between an edge and the center portion and the other gauge being at the other edge. The apparatus has a first actuator for adjusting the linear dimension at one end portion of a sheet material and a second actuator for adjusting the linear dimension at the other end portion. The first and second actuators together act to adjust the linear dimension across the entire widthof the material including a central portion intermediate the end portions. A third actuator(s) adjusts the central portion linear dimension in relation to the end portions. The gauges are coupled to a controller means. The controller means periodically activates the first and second actuators together with the gauges at the end portions and the third actuator separately with the one gauge at the center portion. The first and second actuators are energized, upon activation, to restore the end portions to their respective target value(s). The third actuator is energized, upon activation, by the controller means only when the difference between the central portion linear dimension and the linear dimension of one of the end portions deviates from a predetermined amount. When there is such a deviation the third actuator initiates an adjustment(s) that returns the central portion to match the edge value.

Before the detailed description commences, it must be understood that the disclosed apparatuses are only a few of the several on which the method of the present invention can be practiced. The disclosed embodi ments employ systems which can be modified or rearranged without departing from the method of the present invention.

In the. following detailed description, the drawings are referred to, wherein,

FIGS. 1(a), (b), and (c) are examples of material profiles and are cross-section elevation views taken along the lines 1-1 of FIG. 3 through the material at 7 right angle to the direction of elongation.

FIGS. 2(a), (b), and (c) are examples of material machine direction variation and are cross-section elevation views. along the lines 2-2 of FIG. 3 through the material along the direction of elongation.

FIG. 3 is a schematic diagram of one system for controlling the formation of a material in accordance with the present invention.

FIG. 4 is a perspective view of a system for controlling an apparatus having a cross-axis adjustment and end adjustments in accordance with the present invention.

FIGS. 5(a) through (I) are views illustrating the effect of cross-axis adjustment on material profile and the control action of the present invention for the apparatus shown in FIG. 4.

FIG. 6 is a perspective view of a system for controlling an apparatus havinga roll-bending adjustment and end adjustments in accordance with the present invention.

FIG. 7 is one type of control system for a material forming apparatus, such as shown in FIG. 4, presenting a detailed circuit arrangement in accordance with the present invention.

FIG. 8 is another control system for a material forming apparatus, such as shown in FIG. 4, showing a detailed circuit arrangement in accordance with the present invention.

FIG. 9 is a circuit diagram for a timer suitable for use in the control systems shown in FIGS. 4, 7, and 8.

FIG. 10 is another type of control system for a material forming apparatus in accordance with the present invention.

direction of-movement of the material. Typical profiles for sheets 2, 2, and 2" are shown in FIGS. 1(a), 1(b),

and 1(0). The linear dimension variation in the direction of the material movement, machine direction, is also important, since it affects the dynamic profile. Typical sheet machine direction variations for the sheets 2, 2, and 2" are shown in FIGS.'2(a), 2(b),'and 2(a). As an example, consider the profile of sheet 2 in FIG. 1(a). Sheet 2 does not have any profile of sheet 2 in FIG. 1(b) and 2(b) initially has a uniform linear dimension of X acrossthe width. Then there is an apparent profile change due to a variation of AX in the machine direction if a measurement is-taken at two different times. The profile of sheet 2'. shown in FIG. 1(0) and FIG. 2(0) has a AX variation at each end, the central portion is uniformly at X, and there is no variation in the sheet machine direction.

The method of the present invention can be illustrated as practiced by system 1 shown in FIG. 3 for controlling the profile of a material such as an elongated moving sheet 2". Sheet 2" is formed or shaped by a regulator apparatus 3 comprising actuators 4, 5, and 6 spaced along the width of sheet 2" to adjust the profile linear dimension of respective sheet portions. Actuator 4 adjusts the linear dimension of the sheet end portion that passes through it. Actuator 6 adjusts the linear dimension of the sheet end portion that passes through it. Actuators 4 and 6' together adjust the linear dimension across the sheet width including the central portion that is separately adjusted by actuator 5. Thus the adjustment of actuators 4 and 6 interact with the adjustment of the central portion by actuator 5.

On the output side of the regulator apparatus 3 is disposed gauge means 7 for measuring linear dimension in each of the aforementioned sheet portions, such as gauges 8 and 10 positioned near opposite ends of sheet 2" to measure linear dimension in the portions acted on by actuators 4 and 6, respectively, and gauge 9 at the central portion of sheet 2" to measure the linear dimension of the central portion acted on by actuator 5. Gauge means 7 is coupled to a controller means 11 that receives the indications from gauges 8, 9, and 10. The linear dimension measurement of a sheet portion can be a point measurement or an average value of the linear dimension derived from a scan of the portion. Controller means 1] compares the indication from gauge 8 with a target value and energizes actuator 4 to restore sheet 2' at this portion to the desired linear dimension. Similarly, controller means 11 compares the indication from gauge 10 with a target value, and energizes actuator 6 to restore sheet 2 at this end portion to the desired linear dimension. The target value for comparison with the indications from gauges 8 and 10 are preferably the same, to produce a uniform profile. However, the end portion target values can be different to maintain a desired profile taper.

The indication from gauge 9, for the central portion of sheet 2" intermediate the end portions, is compared with the indication from either gauge 8 or 10 in controller means 1 1. If there is a difference between the indications, controller means 11 energizes actuator 5 to restore the central portion to the linear dimension of the sheet end. If the indications from gauges 9 and 8 or 9 and '10 (either combination can be used) are the same, no corrective action through actuator-5 is taken. If these is a-difference between the indication from the gauges 8 and 1 0 and their respective target values, then actuators -4 and 6 together or separately correct the profile across the sheet width to the desired specification.

Normally, the indication from gauge 9 and the indication from one of the end portions are compared to determine the difference and correct the profile so that the linear dimension of the center portion is substantially the same as the linear dimension of the compared end portion, producing a uniform profile. However, the comparison can be arranged to maintain a constant predetermined difference between the end portion indication and the central portion indication and form a crown-shaped or concave-shaped sheet profile, for example. If. the difference between the indication of gauge 9 and gauges 8 or deviates from the predetermined difference, actuator 5 is activated to change the sheet center portion thickness until the predetermined thickness difference is restored.

The advantage of the aforementioned method of operation is readily apparent by reference to the profile and machine direction cross-sections of FIGS. 1 and 2,

respectively. Sheet 2 has a profile with a uniform thickness of target value X in FIG. 2(a) and a constant machine direction target thickness of target value X in FIG. 2(a). With a sheet of this configuration controller means 11 would not energize any of actuators 4, 5, and 6, since the sheet profile is right on target. Assume, for example, sheet profile changes in the manner of sheet 2" in FIG. 1(0) and FIG. 2(0). The machine direction dimension is constant for any one profile point, but the profile has gradually increased to an amount AX at the right and left end portions and the center portion is substantially at the target value X. Controller means 11 energizes actuators 4 and '6 to restore the sheet thickness to the target value X and keep the sheet ends at the same thickness. Actuator 5 is energized in turn to readjust the sheet center portion following adjustment of the sheet end portions. Actuators 4 and 6 and 5 can be energized alternately until sheet 2" is within desired deadbands about the respective target values.

A machine direction variation in sheet 2"is handled uniquely by the control system 1 in accordance with the method of the present invention. When there is a uniform change in the machine direction, the sheet center portion indication is compared with the indication from one of the end portions and the machine direction change is identified. Adjustment of actuator 5 is unnecessary and, if initiated, could require successive adjustments to restore the profile that can be reached simply through adjustment of actuators 4 and 6. Since the actuators 4 and 6 produce a uniform change across the sheet width, when operated in the same direction simultaneously, only these actuators need be energized to correct the sheet profile. For example, assume a profile as in sheet 2 of FIGS. 1(b) and 2(b) with a machine direction variation of AX. The indications from gauges 8, 9, and 10 are the same and off target by a value proportional to AX. Controller means 1 1 energizes actuators 4 and 6. At the same time the indication from gauge 9 is compared with the indication from gauge 10, for example, and, since the indications are equal, actuator 5 is not energized. The machine direction variation in sheet 2' is correctedby actuators 4 and 6 to restore the sheet profile substantially to the target value X. y

A few of the regulator apparatuses on which the present invention can be practiced are described hereinafter as preferred embodiments and not to restrict the application of the method or the control systems.

The regulator apparatus can be a rolling mill 20 (FIG. 4), such as a'rubber calender machine, having a control system 21 that utilizesthe indications from two nuclear transmission gauges 22 and 23 to maintain a uniform profile in a sheet 24 traveling in direction of arrow 320.

The rolling mill 20 is of conventional design and comprises cylindrical rolls 25 and 26 that are mounted in aframe 27. Roll 25 is mounted only forrotational movement about its stationary longitudinal axis. Roll 26 is mounted for rotation about its longitudinal axis, for'vertical movement at opposite ends 29 and 30, and for movement of its longitudinal axis in a plane about a vertical axis, generally referred to as cross-axis movement. The adjustments that alter the sheet profile include a right screw-down motor 28 that positions end 29 of roll 26 and left screw-down motor 30 that positions end 31 of roll 26. Roll 26 is positioned in crossaxis by motor 32. Two motors which are independent and on opposite sides of the calender can be used, instead of a single motor and connecting drive. For more detailed information on the mechanical construction of a rolling mill having a cross-axis, left and right screwdown adjustments, reference is made to the aforementioned U.S. Pat. No. 3,006,225, and to the technical literature on calenders.

For purposes of applying a control system in accordance with the present invention to rolling mill 20, the important features to note are that the profile at the sheet ends is adjusted by varying the spacing between rolls 25 and 26 at the left and right ends using left and right screw-down motors 30 and 28, respectively. The profile across the sheet, including the central portion intermediate the sheet ends can be adjusted uniformly by varying the spacing between rolls 25 and 26 at the left and right ends together, to an equal extent. The profile at the sheet center portion is adjusted by varying the cross-axis position of roll 26 through cross-axis motor 32.

The linear dimension indications are provided by any suitable gauge of conventional design. For example, at the sheet left end portion 40, stationary nuclear transmission gauge 23 provides an output signal, in accordance with convention technique, that is proportioned to sheet thickness-density. Since density is held substantially constant the signal is primarily a function of sheet thickness. Gauge 22 is movable, driven by a motor 41, between a first stationary position at the sheet right end portion 43 and a second stationary position at the sheet central portion 44. Control system 21 automatically positions gauge 22 in one of these positions through a positioner 45 that receives a signal from potentiometer 46 proportional to the position of gauge 22 at input 47. Positioner 45 also has an input 48 connected through a single-pole, double-throw switch 49 to the arm of one of right position control potentiometers 50 and center position control potentiometer 51. Each of .potentiometers 50 and 51 are. connected to voltage sources (not shown) to provide a position reference signalfTheposi-tion reference signal at positioner input 48 is compared with the signal at input 47 in accordance with conventional technique and any error signal is coupled to gauge driving motor 41 to move nuclear transmission gauge 22 to the pre-set position. a

The output from each of nuclear transmission gauges 22 and 23 is preferably already processed in separate measuring circuits (not shown) and provision in made for standardization, as set forth indetail in US. Pat. No. 2,829,268, to H." R. Chope, issued Apr. l, 1958. The output from nuclear transmission gauge 23 is coupled to a controller 55 that has a target 56 that provides a target signal proportional to the desired target value of thickness for the left end portion 40. The controller 55 is of conventional arrangement and compares the target signal and gauge output signal and produces an error signal proportional to any difference therebetween. The error signal is. coupled to singlepole, double-throw disconnect switch 60 having an arm 81 shown connected to left screw-down motor 30 through a contact 57 and having an unconnected contact 58. The error signal energizes left screw-down motor 30 to restore .the profile of sheet 24 at end portion 40 to the target linear dimension.

The output from nuclear transmission gauge 22 must be switched to the adjustment that affects the sheet portion where the nuclear transmission gauge 22 is positioned. The output from nuclear transmission gauge 22 is coupled through a recorder 61 to a controller 62. The output of controller 62 is coupled through an actuator selector 63 to the right screwdown motor 28 when the nuclear transmission gauge 22 is at the right end portion position and to the crossaxis motor 32 when the nuclear transmission gauge 22 is at the center portion position. The operation of actuator 63 is symbolized by switch 64 having an arm 65 connected to the output of controller 62 and movable to a contact 66 to energize right screw-down motor 28 or to a contact 67 to energize cross-axis motor 32. Positioner 45 preferably provides a signal on line 500 to deactivate controller 62 and recorder 61 when nuclear transmission gauge 22 is moving from one position to the other.

Controller 62 is of conventional design and compares the output signal from nuclear transmission gauge 22, received at input 70, with one of two targets selected by single-pole, double-throw target selector switch 71. Target selector switch 71 has an arm 72 connected to the controller target input 73. and isoperable to engage a contact 74 that connects controller input 73 to the target signal from target 56, the target signal used to maintain the sheet left end portion linear dimension, or to engage contact 75 that connects the controller input 73 to the output of gauge 23.

The operation of control system 21 is automatically programed by a timer 76 to perform a duty cycle when nuclear transmission gauges 22 and 23 are first positioned at their respective end portions 43 and 40 to maintain the linear dimension of the sheet end portions 43 and 40 by adjusting the spacing between the ends of rolls 25 and 26. Secondly, for a successive time period the right and left screw-down motors28 and 30 are deactivated, suspending the control action at the sheet 'end portions 40 and 43 by placing disconnect switch arm 81 at contact 58,- opening the control loop, and connecting selector switch 64 to cross-axis motor 32. Nuclear transmission gauge 22 is positioned at the sheet center portion 44 to adjust the cross-axis position of roll 26, if there is a difference between the indications of nuclear transmission gauges 22 and 23. Timer 76 periodically operates a relay 78 that actuates switches 49, 60, 64, and 71, as indicated by dotted lines 79. The duty cycle is repeated'automatically, and the sheet center portion 44 can be inspected on demand by applying a demand signal at input 80 oftimer 76. The position of switches 49, 60, 64, and 74 when the sheet end portions 40 and 43 are being inspected is as shown in FIG. 4 with the switch arms in the positions marked R and when the sheet center portion is being inspected, the switch arms are in the positions marked C.

The control action of system 21 with reference to the cross-axis position of roll 26 is illustrated in FIG. 5. In FIG. 5(b) sheet 24 is shown with a uniform profile of target linear dimension X and the corresponding cross axis position is shown in FIG. 5(a), where the axis of roll 25 (FIG. 4) is A-A, the axis of roll 26 (FIG. 4) is B-B, and the angle therebetween is 0,. No correction of the sheet profile would be initiated. If the sheet center portion 44 narrows to linear dimension Y without any machine direction variation, FIG. 5(d), nuclear transmission gauge 23 (FIG. 4) measures the linear dimension X at sheet end portion 40 and nuclear transmission gauge 22 measures the linear dimension Y of sheet center portion 44. The output signal from controller 62 repositions the cross axis of roll 26 to an angle 0 FIG. 5(c), less than angle 0,, narrowing the sheet end portions 40 and 43. When the nuclear transmission gauge 22 resumes its position at sheet end portion 43, the right screw-down motor 28 and left screwdown motor 30 increase the spacing between the ends of roll 25 and 26 to restore the profile to a uniform linear dimension X.

The correction for machine direction variation by control system 21 is illustrated by assuming a cross-axis angle of 0,, FIG. 5(e), and a profile increased to a linear dimension of X AX by a machine direction change, FIG. 50). When nuclear transmission gauge 22 is in its position at center portion 44 the difference between the indication of nuclear transmission gauges 22 and 23 v is zero and no change in cross axis is initiated. If cross axis had been changed, the sheet end portions 40 and 43 would have changed and subsequent adjustment of the left and right screw-down motors 28 and 30 would have brought the sheet center portion back to the target linear dimension. One advantage of the use of center and end portion indications to determine if cross-axis adjustment is necessary is to reduce the number of adjustments that are needed to bring the sheet profile back to target.

Another regulator apparatus on which the method of the present invention can be practiced is illustrated in FIG. 6, wherein a metal sheet is formed or shaped by a rolling mill 91, having roll bending. Rolling mills with other types of rolling bending apparatus can be used equally as well with the present invention. Sheet 90 moves between work rolls 92 and 93. Mill 91 includes backing rolls 94 and 95 and mechanisms 98 and 99 for applying pressure against backing roll 94 at each of ends 96 and 97, respectively, driven by separate right and left screw-down motors 100 and 101, respectively. A more detailed description of the mechanisms'98 and 99 can be found in the technical literature, or more particular in U.S. Pat. No. 2,792,730, to G. Cozzo, issued May 21, 1957.

The work roll 93 is rotatable about a stationary axis and supported to prevent bending byauxiliary backing rolls (not shown) as in the aforementioned U.S. Pat. No. 2,792,730. Work roll 92 is rotatable aboutan axis that is stationary at the ends and can be bent inwardly toward the sheet movement direction 102, intermediate the ends, by an auxiliary backing roll 103 in rolling contact with work roll 92. Auxiliary backing roll 103 exerts a controllable pressure against work roll 92 and is rotatably carried by a yoke 104 mounted on ram 105 working in a hydraulic cylinder 106. Cylinder 106 is mounted on a fixed beam 107 with its axis intersecting the axis of rotation of working roll 92 and is positioned to wedge the related axial portion of work roll 92 between the rolls 95 and 93 and resist bowing of the work roll 92.

The force exerted by auxiliary backing roll 103 is controlled by a hydraulic system 110 including a solenoid controlled valve 111 coupled to cylinder 106 through pipe 112 and suitably coupled to a pressurized fluid source (not shown) through pipe 113 and to a return manifold through pipe 114. Valve 111 is arranged so that, depending upon the signal at input 115, more or less of the pressurized fluid led to valve 111 through the pipe 113 is returned through pipe 49 to adjust the pressure within valve 111, and the connecting pipe 112 communicates this adjusted pressure to the cylinder 106 thereby controlling the bending of work roll 92. The profile of sheet 90 is maintained to desired specification by a control system 120 comprising a gauge means 121 and controller means 122. The gauge means 121 includes several gauges, for example, two gauges 123 and 124 coupled to controller means 122, and disposed on sheet 90 to measure the linear dimension of sheet 90 at the end and center portions. Gauge 124 can serve to inspect one end portion and move to the center in the same manner and using the apparatus shown in and described for FIG. 4. Alternatively, a third gauge 125 can be added to inspect the sheet center portion. Controller means 122 receives the linear dimension measurements from the gauges and energizes the left screw-down motor 100 when the indication for the left end portion deviates from a target value, and energizes the right screw-down motor 101 when the right end portion deviates from a target value, usually the same target value as used for the sheet left end portion.

, The indication from the sheet center portion is compared with the indication from one of the sheet end portions is accordance with the present invention. The difference signal is coupled to valve input 115 to alter the degree of bending of work roll 92 and change the linear dimension of the sheet center portion. If the indications from the sheet center and one of the end portions are the same, no adjustment of the roll bending occurs. Any correction for profile change due to machine direction variation is provided by adjustment of the left and right screw-down motors and 101, returning the sheet profile toa uniform target value.

As mentioned previously, other regulator apparatuses used to form or shape materials can be adapted to the apparatus and systems of the present invention. The combination of gauges in the control system can be selected to fit theparticular needs of the manufacturing process. The specific control system circuit can take a number of forms. The control systems .130 and 131 illustrated in FIGS. 7 and 8, respectively, are examples of unique arrangements of circuit elements to carry outthe present invention.

Control system FIG. 7) is specifically designed for the apparatus embodiment shown in FIG. 4, although it can be utilized with other apparatus. Each of nuclear transmission gauges 22 and 23 comprises a radioactive source 401 and detector 131 disposed on opposite sides of sheet 24. The output from each of detectors 131 is proportional to the linear dimension of the sheet 24 at the respective gauge positions and is coupled to separate measuring servos 132 in a conventional manner. The comparison between the output of detectors 131 and one or more targets previously described in reference to the controllers 55 and 62 (FIG. 4) is accomplished by three computer bridges, identified as left computer 135, right computer 136, and center computer 137. Computers 135 and 136 are identical in arrangement and of conventional design, comprising two zeroing potentiometers 138 and 139, a repeat slide-wire potentiometer 140, a target potentiometer 141, and a power source such as battery 321. The arm on the target potentiometer 141 is connected to ground 142 and the repeat slidewire arm is coupled to the input of a DC amplifier 143 having an input terminal 322 connected to ground 142, so that the difference between the voltage setting of the repeat slidewire potentiometer arm and target potentiometer arm appears between the input terminal 144 and ground 142 of amplifier 143. The measuring servos 132 drive the respective repeat slidewire potentiometers as indicated by dotted lines 145 to a position proportional to the output from the respective detector 131. The target potentiometer arms are ganged and set at corresponding positions for adjustment by a single target set knob 146 as indicated by dotted lines 147.

The operation of the left and right computer bridges follow the same pattern. In the left computer bridge 135 for example, the arm of target potentiometer 14 1 is set and the position of the arm of repeat slidewire potentiometer 140 depends on the output of detector 131. The target potentiometer 141 and repeat slidewire potentiometer 140 are identical in construction, electrically and mechanically, so that when the respective arms are at the same position the potential difference between the arm settings is zero. In other words, when the gauge 23 is measuring the same thickness as the thickness represented by the setting of the arm of target potentiometer 141, the output from left computer bridge 135 is zero. Deviations of the measured thickness from target are represented by a signal from left computer bridge 135 proportional to the magnitude of the deviation and with a polarity indicative of thickness than target thickness.

The actuator for the sheet right end portion (screwdown motor 28),,FIG. .4, is energized by-the output signal from right computer bridge 136 coupled from amplifier 144 througha normally closed contact 150.

The polarity of the output signal controlsthe direction of movement of the actuator necessary to reduce the output signal to zero and attain the target thickness. Similarly, the actuator for the sheet left end portion (screw-down motor 30) is energized by the output signal from left computer 135 through a normally closed contact 151, and the actuator acts to change the sheet thickness and reduce the output signal to zero. Contacts 150 and 151 areassociated with a relay 153 energized at selected times by a timer 152. The positioner switch 49 (FIG. 4') is in the R position when relay 153- is not energized. Accordingly, with the arrangeportions are mainenergized and the controlaction at the right and left end portions is interrupted by contacts .150' and l5l opening. Positioner switch 49 goes to the C position moving nuclear transmission gauge 22 to the sheet center position.

The comparison of the output signal from nuclear transmission gauges 22 and 23 when gauge 22 is in the center position is accomplished by center computer bridge 137. The measuring servos 132 drive the arms of separate'slidewire potentiometers 160 and 161 as indicated by dotted lines 165 and 166, respectively. Center computer bridge 137 is completed by zeroing potentiometers 162 and 163 and a power supplyas represented as battery 164. The arm of repeat slidewire potentiometer 161 is grounded and the arm of repeat slidewire potentiometer 160 is coupled to the input terminal 167 of a DC amplifier, 168 having the other input terminal 323 grounded at 142. The cross-axisactuator (motor 32), FIG. 4, is energized by the outputof amplifier 168 through normally open contact 170. Contact 170 is closed when relay 153 is energized corresponding to the time when the sheet center portion is being inspected as indicated by dotted line 324. When timer 152 de-energizes relay 153 nuclear transmission gauge 22 resumes its position at the sheet right end portion and control system 130 resumes adjustment of the sheet end portions.

The electrical and mechanical construction of repeat slidewires 160 and 161 are identical so that when the respective arms are in corresponding positions it is the same potential setting and a net potential difference therebetween is zero. The arms of the potentiometers 160 and 161 are coupled to their respective measuring servos and set up so that, when the same sheet thickness is being measured, the arms are driven to corresponding settings and the potential difference between the arms is zero. If the center sheet thickness measured by gauge 22 increases or decreases relative to the sheet end portion thickness measured by gauge 23, the polarity of the output signal from center computer 137 indicates the direction of the change and the signal amplitude is proportional to the relative difference.

same as the indication from the left end portion when a machine direction variation occurs'and the cross-axis actuator will not be energized. At this time amplifier 168 receives a zero input signal since the voltage settings of repeat slidewire potentiometers 160 and 162 are equal. However, any difference between these indications will be used to energize the crossaxis actuator to change the sheet thickness in the manner that, cooperating with the other actuators, will return the sheet to the target thickness and reduce the output of center computer bridge to zero.

Compensating source 325 (shown'in dotted lines) can be inserted at the input 167 of amplifier 168. Source 325 can be a regulated DC voltage source, having a-voltage equal to the desired difference to be maintained between indications for the sheet end and center portions. The polarityzof source 325 is such that the voltage at the arms of repeat slidewire 160 is compensated (for example, partially bucked out) to renderthe voltage appearing across the input terminals 167 and 323 of amplifier 168 at a zero value when the sheet center portion is at the desired greater thickness than the sheet end portions. Compensating source 325 can be eliminated, directly coupling the arm of repeat slidewire .160 to amplifier input 167 and the predetermined difference between sheet center and end portions is reduced to zero to maintain the sheet center and end portions-at the same thickness. It is also apparent that circuits can be added to prevent operation of the actuators for very small differences between an indication and a target. These circuits establish deadbands of operation and are of conventional design.

Control system 402 (FIG. 8) is a modification of the control system of FIG. 7, eliminating and rearranging some components, and like parts have been identified by the same reference numeral. Instead of having three separate computer bridges as in control system 130, control system 402 switches the repeat slidewire potentiometers of the right and left computer bridges and 136 to form the center computer bridge 137. FIG. 8 shows control system 131 connected to form the center computer bridge 137.

The center computer bridge 137 in FIG. 8 is composed of a repeat slidewire 190, connected at one end through switches 192 and 200 to one end of zeroing potentiometer 193 and at the other end throughswitches 191 and 201 to one end of zeroing potentiometer 194. The other ends of zeroing potentiometers 193 and 194 are connected across the ends of a repeat slidewire potentiometer 195. Center computer bridge 137 is energized by a power source represented by battery 196. The arm of repeat slidewire potentiometer 195 is driven by the measuring servo of nuclear transmission gauge 22 (as indicated by dotted line 206) and grounded at 142 through switch 197. The arm of repeat slidewire is driven by measuring servo 132 of nuclear transmission gauge 23 (as indicated by dotted line 206) and is connected to an input terminal 216 of an amplifier 198 which has its other input terminal grounded at 142. The output of amplifier 198 is coupled through switch 199 to the cross-axis actuator, motor 32.

With center computer bridge 137 (FIG. 8) connected as just described, the signal at the input of amplifier 198 is zero when the indications'at the sheet center portion 44 and the left sheet end portion 40 are the same. Any difference in indications is developed as a signal at the input of amplifier 198 and coupled to the cross-axis actuator motor 32 to correct the sheet profile at the center portion 44.

Control system 402 is rearranged to form computer bridges 135 and 136 by actuating switches 191, 192, 197, 199, 200, and 201 by means of relay 153 (as indicated by the dotted lines 202). The aforementioned switches are in the position illustrated in FIG. 8 when relay 153 is energized by timer 152, as well as the positioner switch 49 being in the C position. When relay 153 is de-energized positioner switch 49 'goes to the R position, and switches 200 and 201 connect one end of zeroing potentiometers 193 and 194 to a'target-potentiometer 205 having its arm connected to ground 142. Switches 191 and 192 connect opposite ends of repeat slidewire 190 to an end of zeroing potentiometers 210 and 211, and computer bridge 136 is completed by a target potentiometer 212 having its arm connectedto ground 142 and a power supply represented by battery 213. Switch 197 connects the arm of potentiometer 195 to one input terminal 214 of an amplifier 215. The other input terminal of amplifier 215 is at ground 142. The output of amplifier 215 is coupled to the actuator 30 that controls the left end portion 40. Switch 199 connects the output of amplifier 198 to the actuator that controls the right end portion 43.

Control system 402 shifts between the two previously describedarrangements to maintain the profile of sheet 24 at a desired target set by target knob 220 that adjusts the position of the arms of target potentiometers 205 and 212.

The duty cycle of the control systems 130 and 402 is programed by the timer 152. One of several suitable timers 152 switches previously described is energized when a switch 231 is closed by cam follower 232 to connect a power supply represented by battery 233 in series with relay coil 153. Cam follower 232 rides on a cam wheel 230 driven by a constant speed motor (not shown) in the direction of arrow 235 and comprises a follower arm 236 that controls switch 231 and is biased by a spring 237 toward cam wheel 230 against a fixed support 238. Cam wheel 230 has a notch 239 in which a roller 240 at the end of follower arm.236 can ride, allowing switch 231 to close for a portion of each revolution. During this time portion the nuclear transmission gauge 22 is at the sheet center position to adjust the cross-axis actuator, if necessary. When the roller 240 rides on the unnotched rim of cam wheel 230 the contacts 231 are open and the nuclear transmission gauges 22 and 23 are at the sheet end positions. In programming the duty cycle, it is important that the time period for inspecting the sheet center portion 44 is sufficient to provide for corrections until none are required or a fixed number, allowing for transport lag in order to check each correction.

The indications derived from the control systems 130 and 402 are point measurements representing the linear dimensions of the sheet center and end portions. Another type of indication that can be used with the present invention is zone averaging, wherein 'a gauge scans a zone, integrates the linear dimension values and arrives at an average or anaverage deviation from a target for the zone which is used for comparison purposes or to-initiate an appropriate control action. A nuclear transmission gauge arranged with apparatus to provide zone average indications is described in U.S. Pat. No. 3,000,438, to F. M. Alexander, issued Sept. 19,. 1961. An' application of this approach to material profile control in accordance with the present invention is illustrated by control system 250 in FIG. 10.

Generally, the operation of control system 250 is to scan an end portion 260 of moving sheet 270 with a nuclear transmission "gauge 261 and simultaneously scan at an equal rate the opposite end portion 262 of equal length as portion 260 with nuclear transmission gauge 263. The deviation of linear dimension indications from a target for the scan of end portion 260 are. integrated (averaged) to produce a signal proportional to the average value. The average value is used to control the left end portion actuator 264. Similarly, a signal proportional to the average of the deviations from a target for the scan of right end portion 262 controls the right end portion actuator 265. The aforementioned operation continues until a control unit 266 moves nuclear transmission gauge 262 to the center to scan center portion 267 simultaneously as nuclear transmission gauge 261 rescans left end portion 260. The average values from scans of end portion 260 and center portion 267 are compared and the difference, if

any, controls the cross-axis actuator 268 to initiate correction of the sheet center portion. If there is only a machine direction variation in sheet 270, the inspectionof the sheet center portion 267 will not result in an adjustment of the cross-axis actuator 268. The adjustment of the left and right end portion actuators 264 and 265 restores sheet 270 to the desired profile.

The hardware that makes up control system 250 is conventional and is shown in combination to some detail in FIG. 10. The control system 250 is essentially an arrangement of the apparatus described in the aforementioned U.S. Pat. No. 3,000,438 to practice the present invention.

The scanning movement as well as the repositioning of nuclear transmission gauge 261 is provided by a scanning controller 280 that receives inputs from the position sensors 281 and 282 for gauges 261 and 262 respectively and energizes gauge positioning motors 283 and 284. The duty cycle, i.e., period of time that the gauges are inspecting the end portions 260 and 262, and the period of time the gauges are inspecting the sheet end portion 260 and center portion 267 is determined by control unit 266. The output from nuclear transmission gauge 261 is coupled to a measuring servo 285 that drives the arm of a repeat slidewire 286 (as indicated by dotted line 292) in a computer bridge 287 having a target potentiometer 288. The difference between the voltage setting of the arm of target potentiometer 288 and the arm of repeat slidewire potentiometer 286 is coupled to an integrator 289.

Integrator 289 performs three functions. First, it receives the output of computer bridge 287 and integrates same to produce a signal proportional to the average value of derivations of the sheet end portion 260. Next, it reads out by coupling the signal through normally closed switch 290 to left end portion actuator 264. Third, it resets, by discharging. the signal (preferably'stored across an integrating capacitor) to prepare for the next scan and control action. These steps are programmed in relation to the movement of the gauges 261 and 263 by control unit 266 as indicated by dotted line 291.

Nuclear transmission gauge 263 is movable to one position to scan sheet end portion 262 and to a second position to scan sheet center portion 267. Scanning control 280 provides for this movement in response to program instructions received from control unit 266. When nuclear transmission gauge 263 is in position to scan sheet end portion 262, nuclear transmission gauge 261 is in position to scan sheet end portion 260. The scans commence together and .terminate together.

The output from nuclear transmission gauge 263 is coupled to a measuring servo 300 thatdrives the arm of a repeat slidewire 301 in a computer bridge 302 having a target potentiometer 303. Target potentiometers 288 and 303 have their arms ganged together, adjustable by a target knob 304 (as indicated by, dotted line 305), and are positioned at corresponding points to provide the same reference voltage settings. The output of computer bridge 302, which is a signal proportional to the difference between the voltage settings of the arms of repeat slidewire 301 and target potentiometer 303, is coupled to an integrator 306 that performs the same functions as integrator 289 and is programmed by control unit 266, as indicated by dotted line 291. The readout from integrator 306 is a signal proportional to the average of the deviations of the linear dimension in the scanned sheet end portion 262. The output signal is coupled to right end actuator 265 through a normally closed switch 307 to initiate the appropriate corrective action. Control of the sheet end portions 260 and 262 can continue with successive simultaneous scans by the nuclear transmission gauges 261 and 263.

Periodically the sheet center portion 267 is inspected. Control unit 266 initiates movement of nuclear transmission gauge 263 to the center position and opens normally closed contacts 290 and 307 as indicated by dotted line 291 to deactivate the sheet correction by left and right end portion actuators 264 and 265. Nuclear transmission gauge 261 commences scanning of the sheet left end portion 260 at the same time as the nuclear transmission gauge 263' commences scanning of sheet center portion 267 and they terminate their scans at the same time. The output signals from integrators 289 and 306 are coupled to a comparator 310 that takes the difference between these signals and provides an output signal proportional to this difference to a normally open switch 311. Contact 311 is closed by control unit 266 at the time switches 290 and 307 are opened, to couple the output signal from comparator 310 to cross-axis actuator 268.

The operation of control system 250 during inspection of the sheet center portion 267 is such that, if the sheet end portion 261 has the same average linear dimension as the sheet center portion, no correction of the sheet center portion 267 occurs. If a machine direction variation has changed the sheet profile, the correction is provided by the subsequent adjustment of the left and right end portion actuators 264 and 265 6 which restore the entire sheet profile uniformly to the target value.

The duty cycle for control system 250 should allow sufficient time for several corrections of the sheet center portion 267 and to check these corrections, taking into accountthe sheet transport lag.

It is apparent that the method of the present invention has application to regulating apparatuses of many kinds. The control systems described herein are several preferred arrangements for practicing the present invention. Modifications, rearrangement and new embodiments of these control systems can be made without departing from the scope of the present invention as defined in the attached claims.

What is claimed is: v

1. Amethod of maintaining a property of amaterial using apparatus that has a first and second control means for separately adjusting the material property at the end portions respectively and together adjusting the property across the entire material width, and third control means for separately adjusting the property of a third portion of said material intermediate said ends in relation to the property at said end portions comprising the steps of:

adjusting said first and second control means to maintain the property at said end portions of the material at target values, adjusting said third control means only when there is more than a predetermined difference at the same time between said third portion property and the property at one of said end portions.

2. The method as described in claim 1 wherein said adjusting of said third control means comprises the steps of:

measuring the property at one end portion,

measuring the property at said third portion,

simultaneously comparing said measurements to indicate the difference, and

adjusting said control means only where there is more than a predetermined difference between said third portion property and said one end portion property to restore said predetermined difference. 3. A method of maintaining the profile of a material using apparatus that has a first and second control means for separately adjusting the material linear dimension at the end portions respectively and together adjusting the linear dimension across the entire material width, and third control means for separately adjusting the linear dimension of a third portion of said material intermediate said ends in relation to the material dimension at said end portions comprising the steps of:

simultaneously comparing the linear dimension value of one of said end portions and said third portion,

adjusting said first and second control means to maintain said end portions of the material at first and second target values respectively,

adjusting said third control means only when said comparison indicates there is more than a predetermined difference between said third portion linear dimension and one of said end portion linear dimensions.

4. A method of maintaining a property of a material using apparatus that has a first and second control means for separately adjusting the material property at the end portions respectively and together adjusting the adjusting said first and second control means to maintain the property at said end portions of the material at target values, temporarily stopping adjustment of said first and second control means, and then adjusting said third control means only when there is a difference at the same time between said third portion property and the property of one of said end portions. v 5. The methodv as described in claim 4 wherein said adjusting of said third control means comprises the steps of:

measuring the property at one end portion, measuring the property at said third portion, simultaneously comparing said measurements to indicate the difference, and adjusting said control means only where there is more than a predetermined difference between said third portion property and said one end por-.

tion property to restore said predetermined difference. 6. A method of maintaining a material profile at target values with apparatus that has a first control means for adjusting the material linear dimension at one end portion, second control means for adjusting the material linear dimension at the other end portion, said first and second control means together adjusting the linear dimension across the entire material width, and third control means for adjusting the material central portion linear dimension in relation to said end and said other end portions, comprising the steps of:

adjusting said first and second control means to maintain said one end portion and said other end portion at target values, and adjusting said third control means only when there is a predetermined difference at the same time betweenvsaid central portion linear dimension and one of said one end and said other end linear dimensions to restore said predetermined ifference.

7. The method, as described in claim 6, wherein said apparatus is a mill having a pair of rolls that shape said material, said first control means adjusts the spacing at one end of said rolls, said second control means adjusts the spacing between the opposite end of said rolls, and said third control means adjusts the spacing between the ends of said rolls relative to the spacing between a central portion of said rolls intermediate said ends.

8. The method, as described in claim 7, wherein said third control means adjusts the cross-axis of one of said rolls.

9. The method, as described in claim 7, wherein said third control means bends one of said rolls perpendicular to the direction of material elongation.

10. A method of maintaining a material profile at a target value with apparatus that has a first control means for adjusting the material linear dimension at one end portion, second control means for adjusting the material linear dimension at the other end portion, said first and second control means together adjusting the linear dimension across the entire material width, and third control means for adjusting the material central portion linear dimension in relation to said end and said other end portions, comprising the steps of:

periodically performing the following adjustments: simultaneously comparing the linear dimension value at one of said end portions and said center portion, adjusting said first and second control means to maintain said end portion and said other end portion at said one target value, and adjusting said third control means only when said comparison indicates there is a difference between said central portion linear dimension and one of said end and said other end portions linear dimensions to minimize said difference. 11. The method, as described in claim 10, wherein said apparatus is a mill having a pair of rolls that shape said material, said first control means adjusts the spacing at one end of said rolls, said second control means adjusts the spacing between the opposite end of said rolls, and said third control means adjusts the spacing between the ends of said rolls relative to the spacing between a central portion of said rolls intermediate said ends.

12. The method, as described in claim 11, wherein said third control means adjusts the cross-axis of one of said rolls.

13. The method, as described in claim 11, wherein said third control means bends one of said rolls at the center in the direction of the material elongation.

14. A method of maintaining a property of a material using apparatus that comprises control means for separately adjusting the property of a portion of said material intermediate the ends in relation to the property at the end portions, and gauge means for separately indicating said property at one end portion, and at a portion located inwardly from said one end portion having the indicated property, comprising the step of adjusting said control means only when there is more than a predetermined difference between said inwardly located portion indication and the indication from said end portion.

15. A method of maintaining a property of a material using apparatus that has a first and second control means for separately adjusting the material property at one end portion and the opposite end portion respectively and together adjusting the property across the entire material width, third control means for separately adjusting the property of a third portion of said material intermediate said ends in relation to the pro perty at said end portions, and gauge means for separately indicating said property at one end portion, an opposite end portion, and a third portion intermediate said end portions, comprising the steps of:

adjusting said first and second control means to maintain the indicated property at said end portions of the material at target values,

adjusting said third control means only when there is more than a predetermined difference between said third portion indication and the indication from one of said end portions.

16. A method of maintaining the profile of a material using apparatus that has a first and second control means for separately adjusting the material linear dimension across the entire material-width, third control means for separately adjusting the linear dimension of a third portion of said material intermediate said ends in relation to the materialdimension at said end portions, and gauge means for separately indicating said property atone end portion, an opposite end portion, and a third portion intermediate said end portions,

comprising the steps of:

adjusting said first and second control means to maintain said end portions of thematerial at first and second target values respectively, comparing the indicated linear dimension of one of said end portions and the indicated linear dimension of said third portion, adjusting said third control means only when there is more than a predetermined difference between said third portion linear dimension indication and the-indication from one of said end portion linear dimensions. 17. A method of maintaining the profile of a material using apparatus that has a first and second control means for separately adjusting the material linear dimension at the end portions respectively and together adjusting the linear dimension across the entire material width, and third control means for separately adjusting the linear dimension of a third portion of said material intermediate said ends in relation to the material dimension at said end portions comprising the steps of:

adjusting said first and second control means to maintain said end portions of the material at first and second target values respectively,

simultaneously comparing the linear dimension value of one of said end portions and said third portion,

adjusting said third control means only when said comparison indicates there is more than a predetermined difference between said third portion linear dimension and one of said end portion linear dimensions.

18. A method of maintaining a material profile at a target value with apparatus that has a first control means for adjusting the material linear dimension at one end portion, second control means for adjusting the material linear dimension at the other end portion, said first and second control means together adjusting the linear dimension across the entire material width, and third control means for adjusting the material central portion linear dimension in relation to said end and said other end portions, comprising the steps of:

periodically performing the following adjustments:

adjusting said first and second control means to maintain said end portion and said other end portion at said one target value, and simultaneously comparing the linear dimension value at one of said end portions and said center portion,

adjusting said 'third control means only when said comparison indicates there is a difference between said central portion linear dimension and one of said end and said other end portions linear dimensions to minimize said difference.

19. The method as described in claim 18 wherein said apparatus is a mill having a pair of rolls that shape said material, said first control means adjusts the spacing at one end of said rolls, said second control means adjusts the spacing between the opposite end of said rolls, and said third control means adjusts the spacing between the ends of saidrolls relative to the spacing between a central portion of said rolls intermediate said ends.

20. The method as described in claim 19 wherein said third control means adjusts the cross-axis of one of said rolls.

21. The method as described. in claim 19 wherein said third control means bends oneof said rolls at the center in the direction of the material elongation.

22. A method of maintaining a property of a material using apparatus that has a first and second control means for separately adjusting the material property at one end portion and the opposite end portion respectively and together adjusting the property across the entire material width, third control means for separately adjusting the property of a third portion of said material intermediate said ends in relation to the, property at said end portions, and gauge means for indicating the profile of said property in portions near opposite ends and an intermediate portion across the material, comprising the steps of:

adjusting said first and second control means to maintain said respective end portions at target values and adjusting said third control means to correct for a nonuniform profile, said first and second control means being adjusted together in response to said gauge means if the property profile is substantially uniform and deviates from a desired property value at said intermediate portion by greater than a predetermined amount to restore the material property profile to the desired target values without adjusting said third control means. 23. A method of controlling the thickness of a material passing through two calender rolls using apparatus that comprises control means for adjusting the spacing between rolls at each end of the rolls, and the cross axis of one of said rolls, and gauge means for indicating the property profile comprising the steps of:

comparing the property profile at the center relative to the ends and actuating said control means to adjust the roll spacing and said cross axis when the property profile shows a substantially nonuniform profile, to restore a more uniform profile at a desired specification and adjusts only the roll spacing when the material center property is above a predetermined amount and the profile is uniform, to restore the material to uniform profile at a desired specification.

24. Control apparatus for automatically maintaining I cluding a third actuator for adjusting said property between said end portions relative to the property at the central portion of the material intermediate said end portions, said control apparatus comprising:

at least two gauging means to be located on the output side of said regular apparatus for indicating said property in portions near one end, the opone of said one end and said other end to reduce the deviation to said predetermined amount.

25. Apparatus as described in claim 24 wherein said controller means includes a first means that produces an output signal proportional to the difference between said first portion indication and said first target for energizing said first actuator,

said controller means includes a second means that produces an output signal proportional to the difference between said second portion indication and said second target for energizing said second actuator, Y

said controller means includes a third means that produces an output signal proportional to the difference between said third portion indication and one of said first and second portion indications for energizing said third actuator.

26. Apparatus as described in claim 24 wherein said gauge means comprises a first gauge to be positioned to indicate the property in one end portion, a second gauge to be positioned to indicate the said other end portion, and a third gauge to be positioned to indicate the property at the central portion of said elongated strip, I

each of said first, second and third gauges being coupled to said controller means for energizing said first actuator, second actuator, and third actuator respectively to maintain the strip profile at said first and second targets at said end portions.

27. The invention as described in claim 24 wherein said gauge means comprises a first gauging device to be positioned at said one end portion of said strip and a second gauging device that is to be movable between said other end portion and said central portion,

said controller means periodically deactivating said first and second actuators and moving said second gauging device to said central portion, and

the target for comparison with the center portion indication is the indication from said first gauging device at the time said center portion is inspected.

28. Apparatus as described in claim 24 wherein said gauging means comprises first and second gauges, each of said first and second gauges comprising a measuring servo, and

said controller means comprises, a first computer bridge comprising a first target potentiometer and a first repeat slidewire potentiometer driven by said first gauge measuring servo to provide a first output signal proportional to the difference between the setting of said first target potentiometer and said'first repeat slidewire, a second computer bridge comprising a second target potentiometer and a second repeat slidewire potentiometer driven by the measuring servo of said second gauge to provide a second output signal proportional to the difference between the setting of the second target potentiometer and said second repeat slidewire, athird bridge comprising a third repeat slidewire potentiometer driven by the measuring servo of said first gauge and a fourth repeat slidewire potentiometer driven by the measuring servo of said second gauge to produce a third output signal proportional to the difference between the settings of said third and fourth repeat slidewire potentiometers, first switch means having a first position connecting said first output signal to said first actuator and having a second position, second switch means having a first position connecting said second output signal to said second actuator and having a second position, third switch means having a first position and having a second position connecting said third output signal to said third actuator, and timer means 'operably arranged to place said first, second and third switch means simultaneously in said first positions for a period of time and to simultaneously place said first, second, and third switch means periodically in said second positions for a successive time period.

29. Apparatus as described in claim 24 wherein said gauging means comprises first and second gauges, each of said first and second gauges comprising a measuring servo, and

said controller means comprises, a first computer bridge comprising a first target potentiometer and a first repeat slidewire potentiometer driven by said first gauge measuring servo to provide a first output signal proportional to the difference between the setting of said first target potentiometer and said first repeat slidewire, a second computer bridge comprising a second target potentiometer and a second repeat slidewire potentiometer driven by the measuring servo of said second gauge to provide a second output signal proportional to the difference between the setting of the second target potentiometer and said second repeat slidewire, a third bridge comprising a third repeat slidewire potentiometer driven by the measuring servo of said first gauge and a fourth repeat slidewire potentiometer driven by the measuring servo of said second gauge to produce a third output signal proportional to the difference between the settings of said third and fourth repeat slidewire potentiometers, first switch means having a first position connecting said first output signal to said first actuator and having a second position, second switch means having a first position connecting said second output signal to said second actuator and having a second position, third switch means having a first position and having a second position connecting said third output signal to said third actuator, and timer means operably arranged to place said first, second and third switch means simultaneously in said first positions for a period of time and to simultaneously place said first, second and third switch means periodically in said second positions for a successive time period, said third and fourth repeat slidewire potentiometers are also said first and second repeat slidewire potentiometers respectively of said first and second bridges and said third switching means includes a changeover switch means that successively connects said repeat slidewire potentiometers to form said third bridge when said first, second and third switch means are in said second positions. 30. Apparatus as described in claim 24 wherein said gauge means comprises a first gauge device .means that averages the property along a first portion of said material near said one end, a second gauge device means that averages the property along a second portion of said material near said other end and is movable to average the property in a third portion intermediate said one and said other ends, said controller means comprising a first controller coupled to said first gauge means arranged to energize said first actuator when the average property deviates from a target, a second controller coupled to said second gauge means and arranged to energize said first actuator when said second gauge means is averaging said second portion and the average deviates from a target, and a' third controller means coupled to said second gaugemeans and arranged to energize said third actuator when the average from said third portion deviates from the average of one of said first and said second portions. I 31. Apparatus as described in claim 24 wherein said gauge means comprises a first gauge device means that averages the property along a first portion of said material near said one end, a second gauge device means that averages the property along a second portion of said material near said other end and is movable to average the property in a third portion intermediate said one and said other ends, said controller meanscomprising a first controller coupled to said first gauge means arranged to energize said first actuator .when the average property deviates from a target, a second controller coupled to said second gauge means and arranged to energize said second actuator when said second gauge means is averaging said second portion and the average deviates from a target, and a third controller means coupled to said second gauge means and arranged to energize said third actuator when the average from said third portion deviates from the average of one of said first and said second portions, said first and second actuators being deactivated when said third portion is being averaged and said third actuator is operating. 32. Apparatus for automatically maintaining a desired thickness profile across the width of an elongated strip formed in continuous fashion between a pair of coacting rolls, comprising means including a first actuator for adjusting the spacing between said rolls at one end portion thereof, means including a second actuator for adjusting the spacing between said rolls at the opposite end portion thereof, means including a third actuator for adjusting the spacing between said ends of said rolls relative to the spacing between a central portion of said rolls intermediate said end portions,

a gauging means located on the output side of said rolls for indicating strip linear dimensions in portions near one end, the opposite end, and central portion of the material, said gauging means being adapted to simultaneously derive a first signal that indicates the thickness at one of said end portions anda second signal that indicates the thickness at said central portion, a

controller means coupled to said gauging means for energizing said first actuator when said indication for said one end portion deviates from a first target to restore the desired dimension, and for energizv ing said second actuator when said indication for said opposite end portion deviates from a second target to restore the desired dimension, and energizing said third actuator only when said second signal indication for said central portion deviates by more than a predetermined amount from the said first signal indication of one of said one end and said other end to reduce the deviation to said predetermined amount.

33. Apparatus as described in claim 32 wherein said controller means includes a first means that produces an output signal proportional to the difference between said first portion indication and said target for energizing said first actuator,

said controller means includes a second means that produces an output signal proportional to the difference between said second portion indication and said target for energizing said second actuator,

said controller means includes a third means that produces an output signal proportional to the difference between said third portion indication and one of said first and second portion indications for energizing said third actuator.

34. Apparatus as described in claim 32 wherein said gauge means comprises a first gauge positioned to indicate the linear dimension in one end portion, a second gauge positioned to indicate the linear dimension in said other end portion, and a third gauge positioned to indicate the linear dimension at the central portion of said elongated strip,

each of said first, second and third gauges being cou pled to said controller means to energize said first actuator, second actuator, and third actuator respectively to maintain the strip profile at said first and second targets at said end portions.

35. The invention as described in claim 32 wherein said gauge means comprises a first gauging device positioned at said one end portion of said strip and a second gauging device movable between said other end portion and said central portion,

said controller means periodically deactivating said first and second actuators and moving said second gauging device to said central portion, and

the target for comparison with the center portion indication is the indication from said first gauging device at the time said center portion is inspected.

36. Apparatus as described in claim 32 wherein said gauging means comprises first and second gauges, each of said first and second gauges comprising a measuring servo, and

said controller means comprisesa first computer said first gauge measuring servo to provide a first ing a second position connecting said third output signal to said third actuaton and timer means operablyarranged to place said first, second and third switch means simultaneously in said first output signal proportional to the e ce positions for a period of time and to simultanebetween the setting of said first target potentiomeously la said first, second, and third switch ter and sfiid first repeat slidewire, a Second 0031- means periodically in said second positions for a R bridge comprising a Second target p successive time period, said third andfourth retlomgter and a Second repeat slidewire p peat slidewire potentiometers are also said first tiometer driven y e measuring servo of said and second repeat slidewire potentiometers Second gauge to prevlde a Second Output Signal respectively of said first and second bridges and Propottlonal to the difference Petween the settitfg said third switching means includes a changeover of the Second mgtert potetmlometer and Sam switch means that successively connects said resecond repeat Shdewre a thud bridge comprising 1 5 peat slidewire otentiometers-to form said third a third repeat slidewire potentiometer'driven by bridge when said first sec'end and third Switch the measuring servo of said first gauge and a fourth means are in a second positions repeat slidewire potentiometer driven by the mea- 33 Apparatus as described in claim 32 wherein Sufmg Servo f Sald seconfl gauge to Pt a said gauge means comprises a first gauge device thrd output slgnaipropomonal to the dlfference means that averages the material linear dimension between the settings of said third and fourth repeat aleng a first portion f said material near Said one slidewire potentiometers, first switch means havend, a second gauge device means that averages ing a first pqsition connecting Said first output the material linear dimension along a second porignat to said first ectuator and having a seeonf tion of said material near said other end and is position, second switc means i g a first movable to average the material linear dimension tion connecting said second output signal to said in a third portion intermediate said one and Said second actuator and having a second position, other ends t Sw'tch f? havmg a f f and said controller means comprising a first controller mg a secondposltion connectlng said thlld output coupled to said first gauge means arranged to enen signal to said third actuator, and timer means gize said first actuator when the average linear operably arranged to place Said first second and dimension deviates from a target a second conft Switch mean? Simultaneously in said first troller coupled to said second gaug e means and arposmons for of and to "l ranged to energize said second actuator when said ously plac? 5 i l and q i Swltch second gauge means is averaging said second pormeans periodlcallym said second positions for a successive time period. 37. Apparatus as described in claim 32 wherein said tion and the average deviates from a target, and a third controller means coupled to said second gauge means and arranged to energize said third gauging means comprises first and second gauges, each of said first and second gauges comprising a measuring servo, and

said controller means comprises a first computer bridge comprising a first target potentiometer and actuator when the average from said third portion deviates from the average of one of said first and said second portions.

39. Apparatus as described in claim 32 wherein said gauge means comprises a first gauge device a first repeat slidewire potentiometer driven by said first gauge measuring servo to provide a first means that averages the material linear dimension along a first portion of said material near said one output signal proportional to the difference 4 between the setting of said first target potentiomea 9 gauge, means that averages ter and said first repeat slidewire, a second comh material lmear dm lenslon'along a second t" enter bridge comprising a second target noten tion of said material near said other end and is tiometer and a second repeat slidewire potenf F to f the matenal linear dlmenslcfn tiefneter driven by the measuring Serve of said m a third portion intermediate said one and said second gauge to provide a second output signal Pther ends proportional t0 the difference between the setting said controller means comprising a first controller of the second target potentiometer and said P f to 531d first gauge means arranged to e second repeat slidewire, a third bridge comprising t f first fictuator when the average a third repeat slidewire potentiometer driven by dltjwnslon devlates f a target, a second the measuring servo of said first gauge and a fourth troller coupled to sand Second gauge means and repeat slidewire potentiometer driven by the mearanged to energize Said Second actuator h Said suring servo of said second gauge to produce a Second gauge means is averaging said Second P third output signal proportional to the difference tion and the average deviates from a g and a between the settings of said third and fourth repeat third Controller means coupled to said second slidewire potentiometers, first switch means havgauge means and arranged to energize said third ing a first position connecting said first output actuator when the average from said third portion signal to said first actuator and having a second deviates from the average of one of said first and position, second switch means having a first posisaid second portions, said first and second actuat tion connecting said second output signal to said second actuator and having a second position, third switch means having a first position and havtors being deactivated when said third portion is being averaged and said third actuator is operating. 

1. A method of maintaining a property of a material using apparatus that has a first and second control means for separately adjusting the material property at the end portions respectively and together adjusting the property across the entire material width, and third control means for separately adjusting the property of a third portion of said material intermediate said ends in relation to the property at said end portions comprising the steps of: adjusting said first and second control means to maintain the property at said end portions of the material at target values, adjusting said third control means only when there is more than a predetermined difference at the same time between said third portion property and the property at one of said end portions.
 2. The method as described in claim 1 wherein said adjusting of said third control means comprises the steps of: measuring the property at one end portion, measuring the property at said third portion, simultaneously comparing said measurements to indicate the difference, and adjusting said control means only where there is more than a predetermined difference between said third portion property and said one end portion property to restore said predetermined difference.
 3. A method of maintaining the profile of a material using apparatus that has a first and second control means for separately adjusting the material linear dimension at the end portions respectively and together adjusting the linear dimension across the entire material width, and third control means for separately adjusting the linear dimension of a third portion of said material intermediate said ends in relation to the material dimension at said end portions comprising the steps of: simultaneously comparing the linear dimension value of one of said end portions and said third portion, adjusting said first and second control means to maintain said end portions of the material at first and second target values respectively, adjusting said third control means only when said comparison indicates there is more than a predetermined difference between said third portion lineaR dimension and one of said end portion linear dimensions.
 4. A method of maintaining a property of a material using apparatus that has a first and second control means for separately adjusting the material property at the end portions respectively and together adjusting the property across the entire material width, and third control means for separately adjusting the property of a third portion of said material intermediate said ends in relation to the material property at said end portions, comprising the steps of: adjusting said first and second control means to maintain the property at said end portions of the material at target values, temporarily stopping adjustment of said first and second control means, and then adjusting said third control means only when there is a difference at the same time between said third portion property and the property of one of said end portions.
 5. The method as described in claim 4 wherein said adjusting of said third control means comprises the steps of: measuring the property at one end portion, measuring the property at said third portion, simultaneously comparing said measurements to indicate the difference, and adjusting said control means only where there is more than a predetermined difference between said third portion property and said one end portion property to restore said predetermined difference.
 6. A method of maintaining a material profile at target values with apparatus that has a first control means for adjusting the material linear dimension at one end portion, second control means for adjusting the material linear dimension at the other end portion, said first and second control means together adjusting the linear dimension across the entire material width, and third control means for adjusting the material central portion linear dimension in relation to said end and said other end portions, comprising the steps of: adjusting said first and second control means to maintain said one end portion and said other end portion at target values, and adjusting said third control means only when there is a predetermined difference at the same time between said central portion linear dimension and one of said one end and said other end linear dimensions to restore said predetermined ifference.
 7. The method, as described in claim 6, wherein said apparatus is a mill having a pair of rolls that shape said material, said first control means adjusts the spacing at one end of said rolls, said second control means adjusts the spacing between the opposite end of said rolls, and said third control means adjusts the spacing between the ends of said rolls relative to the spacing between a central portion of said rolls intermediate said ends.
 8. The method, as described in claim 7, wherein said third control means adjusts the cross-axis of one of said rolls.
 9. The method, as described in claim 7, wherein said third control means bends one of said rolls perpendicular to the direction of material elongation.
 10. A method of maintaining a material profile at a target value with apparatus that has a first control means for adjusting the material linear dimension at one end portion, second control means for adjusting the material linear dimension at the other end portion, said first and second control means together adjusting the linear dimension across the entire material width, and third control means for adjusting the material central portion linear dimension in relation to said end and said other end portions, comprising the steps of: periodically performing the following adjustments: simultaneously comparing the linear dimension value at one of said end portions and said center portion, adjusting said first and second control means to maintain said end portion and said other end portion at said one target value, and adjusting said third control means only when said comparison indicates there is a difference between said central portion linear dimension and one of said end and said other end portions linear dimensions to minimize said difference.
 11. The method, as described in claim 10, wherein said apparatus is a mill having a pair of rolls that shape said material, said first control means adjusts the spacing at one end of said rolls, said second control means adjusts the spacing between the opposite end of said rolls, and said third control means adjusts the spacing between the ends of said rolls relative to the spacing between a central portion of said rolls intermediate said ends.
 12. The method, as described in claim 11, wherein said third control means adjusts the cross-axis of one of said rolls.
 13. The method, as described in claim 11, wherein said third control means bends one of said rolls at the center in the direction of the material elongation.
 14. A method of maintaining a property of a material using apparatus that comprises control means for separately adjusting the property of a portion of said material intermediate the ends in relation to the property at the end portions, and gauge means for separately indicating said property at one end portion, and at a portion located inwardly from said one end portion having the indicated property, comprising the step of adjusting said control means only when there is more than a predetermined difference between said inwardly located portion indication and the indication from said end portion.
 15. A method of maintaining a property of a material using apparatus that has a first and second control means for separately adjusting the material property at one end portion and the opposite end portion respectively and together adjusting the property across the entire material width, third control means for separately adjusting the property of a third portion of said material intermediate said ends in relation to the property at said end portions, and gauge means for separately indicating said property at one end portion, an opposite end portion, and a third portion intermediate said end portions, comprising the steps of: adjusting said first and second control means to maintain the indicated property at said end portions of the material at target values, adjusting said third control means only when there is more than a predetermined difference between said third portion indication and the indication from one of said end portions.
 16. A method of maintaining the profile of a material using apparatus that has a first and second control means for separately adjusting the material linear dimension at one end portion and the opposite end portion respectively and together adjusting the linear dimension across the entire material width, third control means for separately adjusting the linear dimension of a third portion of said material intermediate said ends in relation to the material dimension at said end portions, and gauge means for separately indicating said property at one end portion, an opposite end portion, and a third portion intermediate said end portions, comprising the steps of: adjusting said first and second control means to maintain said end portions of the material at first and second target values respectively, comparing the indicated linear dimension of one of said end portions and the indicated linear dimension of said third portion, adjusting said third control means only when there is more than a predetermined difference between said third portion linear dimension indication and the indication from one of said end portion linear dimensions.
 17. A method of maintaining the profile of a material using apparatus that has a first and second control means for separately adjusting the material linear dimension at the end portions respectively and together adjusting the linear dimension across the entire material width, and third control means for separately adjusting the linear dimension of a third portion of said material intermediate said ends in relation to the material dimension at said end portions comprising the steps oF: adjusting said first and second control means to maintain said end portions of the material at first and second target values respectively, simultaneously comparing the linear dimension value of one of said end portions and said third portion, adjusting said third control means only when said comparison indicates there is more than a predetermined difference between said third portion linear dimension and one of said end portion linear dimensions.
 18. A method of maintaining a material profile at a target value with apparatus that has a first control means for adjusting the material linear dimension at one end portion, second control means for adjusting the material linear dimension at the other end portion, said first and second control means together adjusting the linear dimension across the entire material width, and third control means for adjusting the material central portion linear dimension in relation to said end and said other end portions, comprising the steps of: periodically performing the following adjustments: adjusting said first and second control means to maintain said end portion and said other end portion at said one target value, and simultaneously comparing the linear dimension value at one of said end portions and said center portion, adjusting said third control means only when said comparison indicates there is a difference between said central portion linear dimension and one of said end and said other end portions linear dimensions to minimize said difference.
 19. The method as described in claim 18 wherein said apparatus is a mill having a pair of rolls that shape said material, said first control means adjusts the spacing at one end of said rolls, said second control means adjusts the spacing between the opposite end of said rolls, and said third control means adjusts the spacing between the ends of said rolls relative to the spacing between a central portion of said rolls intermediate said ends.
 20. The method as described in claim 19 wherein said third control means adjusts the cross-axis of one of said rolls.
 21. The method as described in claim 19 wherein said third control means bends one of said rolls at the center in the direction of the material elongation.
 22. A method of maintaining a property of a material using apparatus that has a first and second control means for separately adjusting the material property at one end portion and the opposite end portion respectively and together adjusting the property across the entire material width, third control means for separately adjusting the property of a third portion of said material intermediate said ends in relation to the property at said end portions, and gauge means for indicating the profile of said property in portions near opposite ends and an intermediate portion across the material, comprising the steps of: adjusting said first and second control means to maintain said respective end portions at target values and adjusting said third control means to correct for a nonuniform profile, said first and second control means being adjusted together in response to said gauge means if the property profile is substantially uniform and deviates from a desired property value at said intermediate portion by greater than a predetermined amount to restore the material property profile to the desired target values without adjusting said third control means.
 23. A method of controlling the thickness of a material passing through two calender rolls using apparatus that comprises control means for adjusting the spacing between rolls at each end of the rolls, and the cross axis of one of said rolls, and gauge means for indicating the property profile comprising the steps of: comparing the property profile at the center relative to the ends and actuating said control means to adjust the roll spacing and said cross axis when the property profile shows a substantially nonuniform profile, to restore a more uniform profile at a desired specification and adjusTs only the roll spacing when the material center property is above a predetermined amount and the profile is uniform, to restore the material to uniform profile at a desired specification.
 24. Control apparatus for automatically maintaining a desired property profile across a material passing through a regulator apparatus in continuous fashion, said regulating apparatus having means including a first actuator for adjusting said property at one end portion thereof, means including a second actuator for adjusting said property at the opposite end portion thereof, said first and second actuators together adjusting said property across the entire material width, means including a third actuator for adjusting said property between said end portions relative to the property at the central portion of the material intermediate said end portions, said control apparatus comprising: at least two gauging means to be located on the output side of said regular apparatus for indicating said property in portions near one end, the opposite end, and central portion of the material, controller means coupled to said gauging means for energizing said first actuator when said indication for said one end portion deviates from a first target to restore the desired property; and for energizing second actuator when said indication for said opposite end portion deviates from a second target to restore the desired property, and energizing said third actuator only when said indication for said central portion deviates by more than a predetermined amount from the simultaneous indication of one of said one end and said other end to reduce the deviation to said predetermined amount.
 25. Apparatus as described in claim 24 wherein said controller means includes a first means that produces an output signal proportional to the difference between said first portion indication and said first target for energizing said first actuator, said controller means includes a second means that produces an output signal proportional to the difference between said second portion indication and said second target for energizing said second actuator, said controller means includes a third means that produces an output signal proportional to the difference between said third portion indication and one of said first and second portion indications for energizing said third actuator.
 26. Apparatus as described in claim 24 wherein said gauge means comprises a first gauge to be positioned to indicate the property in one end portion, a second gauge to be positioned to indicate the said other end portion, and a third gauge to be positioned to indicate the property at the central portion of said elongated strip, each of said first, second and third gauges being coupled to said controller means for energizing said first actuator, second actuator, and third actuator respectively to maintain the strip profile at said first and second targets at said end portions.
 27. The invention as described in claim 24 wherein said gauge means comprises a first gauging device to be positioned at said one end portion of said strip and a second gauging device that is to be movable between said other end portion and said central portion, said controller means periodically deactivating said first and second actuators and moving said second gauging device to said central portion, and the target for comparison with the center portion indication is the indication from said first gauging device at the time said center portion is inspected.
 28. Apparatus as described in claim 24 wherein said gauging means comprises first and second gauges, each of said first and second gauges comprising a measuring servo, and said controller means comprises, a first computer bridge comprising a first target potentiometer and a first repeat slidewire potentiometer driven by said first gauge measuring servo to provide a first output signal proportional to the difference between the setting of said first tarGet potentiometer and said first repeat slidewire, a second computer bridge comprising a second target potentiometer and a second repeat slidewire potentiometer driven by the measuring servo of said second gauge to provide a second output signal proportional to the difference between the setting of the second target potentiometer and said second repeat slidewire, a third bridge comprising a third repeat slidewire potentiometer driven by the measuring servo of said first gauge and a fourth repeat slidewire potentiometer driven by the measuring servo of said second gauge to produce a third output signal proportional to the difference between the settings of said third and fourth repeat slidewire potentiometers, first switch means having a first position connecting said first output signal to said first actuator and having a second position, second switch means having a first position connecting said second output signal to said second actuator and having a second position, third switch means having a first position and having a second position connecting said third output signal to said third actuator, and timer means operably arranged to place said first, second and third switch means simultaneously in said first positions for a period of time and to simultaneously place said first, second, and third switch means periodically in said second positions for a successive time period.
 29. Apparatus as described in claim 24 wherein said gauging means comprises first and second gauges, each of said first and second gauges comprising a measuring servo, and said controller means comprises, a first computer bridge comprising a first target potentiometer and a first repeat slidewire potentiometer driven by said first gauge measuring servo to provide a first output signal proportional to the difference between the setting of said first target potentiometer and said first repeat slidewire, a second computer bridge comprising a second target potentiometer and a second repeat slidewire potentiometer driven by the measuring servo of said second gauge to provide a second output signal proportional to the difference between the setting of the second target potentiometer and said second repeat slidewire, a third bridge comprising a third repeat slidewire potentiometer driven by the measuring servo of said first gauge and a fourth repeat slidewire potentiometer driven by the measuring servo of said second gauge to produce a third output signal proportional to the difference between the settings of said third and fourth repeat slidewire potentiometers, first switch means having a first position connecting said first output signal to said first actuator and having a second position, second switch means having a first position connecting said second output signal to said second actuator and having a second position, third switch means having a first position and having a second position connecting said third output signal to said third actuator, and timer means operably arranged to place said first, second and third switch means simultaneously in said first positions for a period of time and to simultaneously place said first, second and third switch means periodically in said second positions for a successive time period, said third and fourth repeat slidewire potentiometers are also said first and second repeat slidewire potentiometers respectively of said first and second bridges and said third switching means includes a changeover switch means that successively connects said repeat slidewire potentiometers to form said third bridge when said first, second and third switch means are in said second positions.
 30. Apparatus as described in claim 24 wherein said gauge means comprises a first gauge device means that averages the property along a first portion of said material near said one end, a second gauge device means that averages the property along a second portion of said material near said other end and is movable to average the property in a third portion intermediate said one and said other ends, said controller means comprising a first controller coupled to said first gauge means arranged to energize said first actuator when the average property deviates from a target, a second controller coupled to said second gauge means and arranged to energize said first actuator when said second gauge means is averaging said second portion and the average deviates from a target, and a third controller means coupled to said second gauge means and arranged to energize said third actuator when the average from said third portion deviates from the average of one of said first and said second portions.
 31. Apparatus as described in claim 24 wherein said gauge means comprises a first gauge device means that averages the property along a first portion of said material near said one end, a second gauge device means that averages the property along a second portion of said material near said other end and is movable to average the property in a third portion intermediate said one and said other ends, said controller means comprising a first controller coupled to said first gauge means arranged to energize said first actuator when the average property deviates from a target, a second controller coupled to said second gauge means and arranged to energize said second actuator when said second gauge means is averaging said second portion and the average deviates from a target, and a third controller means coupled to said second gauge means and arranged to energize said third actuator when the average from said third portion deviates from the average of one of said first and said second portions, said first and second actuators being deactivated when said third portion is being averaged and said third actuator is operating.
 32. Apparatus for automatically maintaining a desired thickness profile across the width of an elongated strip formed in continuous fashion between a pair of coacting rolls, comprising means including a first actuator for adjusting the spacing between said rolls at one end portion thereof, means including a second actuator for adjusting the spacing between said rolls at the opposite end portion thereof, means including a third actuator for adjusting the spacing between said ends of said rolls relative to the spacing between a central portion of said rolls intermediate said end portions, a gauging means located on the output side of said rolls for indicating strip linear dimensions in portions near one end, the opposite end, and central portion of the material, said gauging means being adapted to simultaneously derive a first signal that indicates the thickness at one of said end portions and a second signal that indicates the thickness at said central portion, controller means coupled to said gauging means for energizing said first actuator when said indication for said one end portion deviates from a first target to restore the desired dimension, and for energizing said second actuator when said indication for said opposite end portion deviates from a second target to restore the desired dimension, and energizing said third actuator only when said second signal indication for said central portion deviates by more than a predetermined amount from the said first signal indication of one of said one end and said other end to reduce the deviation to said predetermined amount.
 33. Apparatus as described in claim 32 wherein said controller means includes a first means that produces an output signal proportional to the difference between said first portion indication and said target for energizing said first actuator, said controller means includes a second means that produces an output signal proportional to the difference between said second portion indication and said target for energizing said second actuator, said controller means includes a third means that produces an output signal proportional to the difference between said third portion indication and one of said first and second portion inDications for energizing said third actuator.
 34. Apparatus as described in claim 32 wherein said gauge means comprises a first gauge positioned to indicate the linear dimension in one end portion, a second gauge positioned to indicate the linear dimension in said other end portion, and a third gauge positioned to indicate the linear dimension at the central portion of said elongated strip, each of said first, second and third gauges being coupled to said controller means to energize said first actuator, second actuator, and third actuator respectively to maintain the strip profile at said first and second targets at said end portions.
 35. The invention as described in claim 32 wherein said gauge means comprises a first gauging device positioned at said one end portion of said strip and a second gauging device movable between said other end portion and said central portion, said controller means periodically deactivating said first and second actuators and moving said second gauging device to said central portion, and the target for comparison with the center portion indication is the indication from said first gauging device at the time said center portion is inspected.
 36. Apparatus as described in claim 32 wherein said gauging means comprises first and second gauges, each of said first and second gauges comprising a measuring servo, and said controller means comprises a first computer bridge comprising a first target potentiometer and a first repeat slidewire potentiometer driven by said first gauge measuring servo to provide a first output signal proportional to the difference between the setting of said first target potentiometer and said first repeat slidewire, a second computer bridge comprising a second target potentiometer and a second repeat slidewire potentiometer driven by the measuring servo of said second gauge to provide a second output signal proportional to the difference between the setting of the second target potentiometer and said second repeat slidewire, a third bridge comprising a third repeat slidewire potentiometer driven by the measuring servo of said first gauge and a fourth repeat slidewire potentiometer driven by the measuring servo of said second gauge to produce a third output signal proportional to the difference between the settings of said third and fourth repeat slidewire potentiometers, first switch means having a first position connecting said first output signal to said first actuator and having a second position, second switch means having a first position connecting said second output signal to said second actuator and having a second position, third switch means having a first position and having a second position connecting said third output signal to said third actuator, and timer means operably arranged to place said first, second and third switch means simultaneously in said first positions for a period of time and to simultaneously place said first, second, and third switch means periodically in said second positions for a successive time period.
 37. Apparatus as described in claim 32 wherein said gauging means comprises first and second gauges, each of said first and second gauges comprising a measuring servo, and said controller means comprises a first computer bridge comprising a first target potentiometer and a first repeat slidewire potentiometer driven by said first gauge measuring servo to provide a first output signal proportional to the difference between the setting of said first target potentiometer and said first repeat slidewire, a second computer bridge comprising a second target potentiometer and a second repeat slidewire potentiometer driven by the measuring servo of said second gauge to provide a second output signal proportional to the difference between the setting of the second target potentiometer and said second repeat slidewire, a third bridge comprising a third repeat slidewire potentiometer driven by the measuring servo of said first gauge and a fourth rEpeat slidewire potentiometer driven by the measuring servo of said second gauge to produce a third output signal proportional to the difference between the settings of said third and fourth repeat slidewire potentiometers, first switch means having a first position connecting said first output signal to said first actuator and having a second position, second switch means having a first position connecting said second output signal to said second actuator and having a second position, third switch means having a first position and having a second position connecting said third output signal to said third actuator, and timer means operably arranged to place said first, second and third switch means simultaneously in said first positions for a period of time and to simultaneously place said first, second, and third switch means periodically in said second positions for a successive time period, said third and fourth repeat slidewire potentiometers are also said first and second repeat slidewire potentiometers respectively of said first and second bridges and said third switching means includes a changeover switch means that successively connects said repeat slidewire potentiometers to form said third bridge when said first, second and third switch means are in said second positions.
 38. Apparatus as described in claim 32 wherein said gauge means comprises a first gauge device means that averages the material linear dimension along a first portion of said material near said one end, a second gauge device means that averages the material linear dimension along a second portion of said material near said other end and is movable to average the material linear dimension in a third portion intermediate said one and said other ends, said controller means comprising a first controller coupled to said first gauge means arranged to energize said first actuator when the average linear dimension deviates from a target, a second controller coupled to said second gauge means and arranged to energize said second actuator when said second gauge means is averaging said second portion and the average deviates from a target, and a third controller means coupled to said second gauge means and arranged to energize said third actuator when the average from said third portion deviates from the average of one of said first and said second portions.
 39. Apparatus as described in claim 32 wherein said gauge means comprises a first gauge device means that averages the material linear dimension along a first portion of said material near said one end, a second gauge device means that averages the material linear dimension along a second portion of said material near said other end and is movable to average the material linear dimension in a third portion intermediate said one and said other ends, said controller means comprising a first controller coupled to said first gauge means arranged to energize said first actuator when the average linear dimension deviates from a target, a second controller coupled to said second gauge means and arranged to energize said second actuator when said second gauge means is averaging said second portion and the average deviates from a target, and a third controller means coupled to said second gauge means and arranged to energize said third actuator when the average from said third portion deviates from the average of one of said first and said second portions, said first and second actuators being deactivated when said third portion is being averaged and said third actuator is operating.
 40. Apparatus for maintaining a desired property profile across a material passing through a regulator apparatus in continuous fashion, said regulating apparatus having means including a first actuator for separately adjusting said property at one end portion and a second actuator for separately adjusting said property at the opposite end portion, said first and second actuators together adjusting said property across the entire material width, a tHird actuator for adjusting said property at said end portions relative to the property at an intermediate portion of the material, said apparatus comprising: gauging means responsive to the material property for producing an indication of said property, including an end portion indication, and an intermediate portion indication, means for comparing said intermediate portion indication with said end portion indication and for adjusting said third actuator only when said compared intermediate portion and said end portion indication deviate from each other by more than a predetermined amount to reduce the deviation within said predetermined amount, and for actuating said first and second actuators to restore the desired property profile.
 41. Apparatus for maintaining a desired property profile across a material passing through a regulator apparatus in continuous fashion, said regulator apparatus having means including a first actuator for adjusting said property at one end portion thereof, means including a second actuator for adjusting said property at the opposite end portion thereof, said first and second actuators together adjusting said property across the entire material width, means including a third actuator for adjusting said property between said end portions relative to the property at a central portion of the material, said apparatus comprising: gauging means to be located on the output side of said regulator apparatus for indicating said property in portions near one end, the opposite end, and central portion of the material, means for comparing said central portion indication with one of said end portion indications and for adjusting said third actuator only when said compared central portion and one of said end portion indications deviate from each other by more than a predetermined amount to reduce said deviation within said predetermined amount.
 42. Apparatus for maintaining a desired property profile across a material passing through a regulator apparatus in continuous fashion, said regulator apparatus having means including a first actuator for adjusting said property at one end portion thereof, means including a second actuator for adjusting said property at the opposite end portion thereof, said first and second actuators together adjusting said property across the entire material width, means including a third actuator for adjusting said property between said end portions relative to the property at a central portion of the material, said apparatus comprising: gauging means to be located on the output side of said regulator apparatus for indicating said property in portions near one end, the opposite end, and central portion of the material, controller means coupled to said gauging means for comparing said indication for said one end portion with a first target and for energizing said first actuator to restore said first target, comparing said indication for said opposite end portion with a second target and for energizing said second actuator to restore said second target, and comparing said central portion indication with one of said end portion indications and energizing said third actuator only when said compared central portion indication and one of said end portion indications deviate from each other by more than a predetermined amount to reduce said deviation within said predetermined amount.
 43. Apparatus for maintaining a desired property profile across a material passing through a regulator apparatus in continuous fashion, said regulator apparatus having means including a first actuator for adjusting said property at one end portion thereof, means including a second actuator for adjusting said property at the opposite end portion thereof, said first and second actuators together adjusting said property across the entire material width, means including a third actuator for adjusting said property between said end portions relative to the property at a central portion of the material, said apparatus comprisinG: gauging means for indicating the profile of said property in portions near opposite ends and an intermediate portion across the material, control means coupled to said gauging means for adjusting said first and second actuators, to maintain said respective end portions at predetermined property values, said control means adjusting said third actuator to correct for a nonuniform profile, said control means comparing said profile measurements and if the property profile is substantially uniform and deviates from a desired property value at said intermediate portion by more than a predetermined amount said first and second actuators are adjusted together to restore the material property profile to the desired property values without adjusting said third actuator.
 44. Apparatus for maintaining a desired property profile across a material passing through a regulator apparatus in continuous fashion, said regulating apparatus having means including a first actuator for separately adjusting said property at the opposite end portion, said first and second actuators together adjusting said property across the entire material width, a third actuator for adjusting said property at said end portions relative to the property at an intermediate portion of the material, said apparatus comprising: gauging means for producing profile measurements of said property in portions near opposite ends and an intermediate portion across the material. means responsive to the gauging means for adjusting said third actuator only when the property profile measurements indicate a substantially nonuniform property profile, to restore a more uniform profile, and for actuating only said first and second actuators to restore the desired property profile when the profile is uniform and the said intermediate portion property is greater than a predetermined amount. 